Rice is one of the leading food crops in the world and many different types of rice are consumed. Quality preferences in various countries and regions are diverse. Preference may originate from naturally occurring local plant types which produce grains with specific properties, or be associated with the utensils available for cooking and eating, or with the nature of local foods which accompany rice and also the availability and convenience of cooking methods. For example, chopsticks are associated with the use of sticky rice, curry eaters prefer dry and fluffy rice, instant rice (precooked, dried and then reconstituted) has different properties but convenience of preparation results in some consumers preferring that type of rice. Some consumers prefer highly polished rice which is very white after cooking, other consumers prefer brown rice which has a higher bran and dietary fiber level.
The rice industry, which includes breeders, farmers, processors and marketers, respond to consumer preferences around the world by developing and producing a vast array of varieties and hybrids of rice and products from rice.
Attempts at controlling the cooking characteristics of a rice variety or hybrid deal with determining various physicochemical parameters of breeds of rice and then cross-breeding or hybridization to arrive at proper amylose content, gelatinization temperature, gel consistency, grain dimensions and other such parameters. Broad classifications for amylose are low, medium and high. Classification for gelatinization temperature are low, intermediate and high. Classification for gel consistency are soft, medium and hard. Grain dimensions are used to classify rice as long, medium or short. These tests and classifications are used for milled raw white rice. The tests and classifications are modified when used for parboiled rice. Amylose has been considered as the most important characteristic for predicting rice cooking and processing behavior. The economic value of the rice grain is largely determined by cooking and processing behavior, grade and milling yield.
The breeding into a rice variety of a combination of desirable physicochemical properties, taste, aroma and elongation during cooking results in considerable breeding time, cost and complexity. For the development of hybrid rice it is necessary to add the complexity of breeding in the traits of male sterility and restoration properties. Breeding and parboiling have been the principal way that cooked rice qualities have been imparted to a particular rice in the prior art.
A process or procedure which reduces the need to breed different combinations of physicochemical properties into a rice, and yet obtain differing cooking characteristics normally associated with such differing properties, would significantly improve the efficiency of producing a commercial rice with particular characteristics.